This invention relates to agar gel compositions, a method for making such compositions and a method for applying such compositions as topical dressings to a burn area or other area of skin impairment.
A burn is generally defined as a bodily injury or lesion caused by contact with, or exposure to, heat, chemicals, electricity or radiation. The burning agent, which changes or even destroys the affected tissue, injures and destroys cells by altering the protein component of such cells. In mild burns, there is cellular disorganization in the affected area; while in more severe burns, there is heat coagulation and charring with tissue necrosis.
Burns are customarily defined and classified according to (a) their degree as determined by their depth and the nature of the tissue involved, (b) their extent as determined by the area or percentage of body surface involved, and (c) the nature of the burning agent.
In first-degree burns, which are the least serious, damage is confined to the outer skin layers, or epidermis. Tissue cells, while affected, are generally not destroyed.
Second-degree burns involve the destruction of the epidermis and the upper layers of the dermis (superficial second-degree burns) or all but the deepest layers of the dermis (deep second-degree burns). In second-degree burns, islets of epithelium are left intact, particularly around undestroyed hair follicles and sweat glands. From these islets, there may be spontaneous regeneration of tissue, although healing is slow, and the deeper the burn the slower the healing. In addition, trauma, infection or other causes may impair tissue regeneration and result in full-thickness destruction of the skin. Since second-degree burns uncover nerve endings, the burned areas can be very painful, even from exposure to air.
Third-degree burns are those in which the full thickness of the skin (epidermis and dermis) is destroyed. Since sweat glands and hair follicles are likely to be destroyed, spontaneous regeneration of skin must usually be from the wound edge and, unless the burned area is small and localized, skin grafting is necessary to prevent scarring and to restore function.
Burns may also be classified as fourth-degree and char burns. When the full thickness of the skin and tissue beneath the skin have been destroyed, the burn may be called fourth-degree. A burn may be called a char burn when a body area is destroyed by charring which leaves a black appearance.
In the management of burns, therapeutic coatings and dressings are employed to keep the wound clean, to act as a barrier against external contamination, to suppress bacterial growth at the wound site, to promote healing and reepitheliazation in second-degree or partial thickness burns and to promote the formation of satisfactory granulations tissue in third-degree or full thickness burns as a base for skin grafting.
The therapeutic coatings and dressings may be employed in the form of spreadable and film forming compositions and in the form of impregnated gauze and bandages. The coatings and dressings may be formulated with potent antibacterials such as nitrofurazone or silver sulfadiazine.
It is disclosed in the art that a soluble dressing containing nitrofurazone in a water-soluble base of polyethylene glycols may be applied directly to the lesion or that a gauze or bandage impregnated with the dressing can be used; that a solution containing nitrofurazone dissolves in a water-miscible liquid of polyethylene glycol and water may be sprayed on painful lesions or burns and, upon evaporation of the water, a transparent film of nitrofurazone and polyethylene glycol remains; and that a topical cream containing nitrofurazone in a water-miscible base consisting of glycerin, cetyl alcohol, mineral oil, and ethoxylated fatty alcohol, methylparaben, propylparaben and water may be applied directly to the lesion or that gauze impregnated with the cream can be used. It is also disclosed in the art that a water-miscible cream containing silver sulfadiazine in a vehicle consisting of white petrolatum, stearyl alcohol, isopropyl myristate, sorbitan monooleate, polyoxyl 40 stearate, propylene glycol, methyl paraben and water may be applied to the burn wound as an adjunct for the prevention and treatment of wound sepsis in patients with second- and third-degree burns.